Telangana Grid Interconnection
TGSPDCL Net-Metering & Solar Interconnection Guide
Technical feasibility norms, voltage thresholds, bi-directional metering specifications, and utility liaison for rooftop solar under Southern Power Distribution Company of Telangana Limited.
Distribution Utility Profile
TGSPDCL
Southern Power Distribution Company of Telangana Limited
Operational Jurisdiction
15 Districts CoveredGrid-connected solar net-metering applications and MRT meter testing for all administrative revenue circles in these districts are processed through TGSPDCL divisions:
Key Urban Centers
Hyderabad, Secunderabad, Cyberabad, Nalgonda, Mahabubnagar, Siddipet, Sangareddy
Technical Feasibility & Specs
Interconnection norms & thresholds
Statutory supply voltages, transformer capacity ceiling, and bi-directional meter specifications applicable for solar rooftop connections under TGSPDCL.
Supply Voltage Thresholds
Permissible interconnection supply levels based on total solar inverter AC output capacity:
- LT Single-Phase
- Up to 5 kW (230V single-phase LT supply)
- LT Three-Phase
- Above 5 kW up to 56 kW (415V three-phase LT supply)
- HT 11 kV Supply
- Above 56 kW up to 1,000 kW (11 kV HT supply)
- HT 33 kV Supply
- Above 1,000 kW up to 5,000 kW (33 kV HT supply)
Supply conversion application can be bundled with solar feasibility filing.
Transformer & Load Caps
Statutory limits enforced by regulatory orders during technical scrutiny:
- DTR Capacity Ceiling: 50%
- Cumulative solar generation capacity connected to any distribution transformer cannot exceed 50% of the transformer rated capacity under TSERC Regulation 6 of 2016.
- Contracted Load Limit: Up to 100%
- Residential consumers may install solar capacity up to 100% of sanctioned contracted load; commercial and industrial consumers are capped at 80% of sanctioned load.
- Settlement Cycle
- Monthly net billing adjustment against retail tariff slabs
- Banking Carry-Forward
- Surplus energy credits carry forward across monthly billing cycles within the annual settlement period defined by TGERC tariff orders
Feasibility approval is valid for project execution and agreement signing.
Bi-Directional Net-Meter
Utility hardware specifications and calibration protocols:
- Bi-Directional Net Meter
- DLMS-compliant four-quadrant static bi-directional energy meter (Class 1.0 for LT, Class 0.5s for HT) complying with IS 13779 / IS 14697 and CEA metering regulations
- Solar Generation Meter
- Unidirectional static check meter installed at the inverter AC output to measure gross solar generation
- Protocol Compliance
- DLMS / COSEM protocol compliant with optical communication port
- Testing Laboratory
- TGSPDCL Meter Relay Testing (MRT) Laboratory
Leo Solar handles procurement, lab testing delivery, and installation liaison.
Step-by-Step Workflow
4-Step Interconnection Timeline
From initial feasibility registration on the portal to grid synchronization and commissioning certificate release with TGSPDCL.
Feasibility Application and Service Validation
Online application filing on the TGSPDCL Solar Portal or PM Surya Ghar National Portal using Unique Service Connection Number (USCNO). Section Officer reviews local distribution transformer headroom.
Technical Feasibility Sanction and Agreement Execution
Issuance of formal technical feasibility clearance letter followed by signing of the standard bipartite Net Metering Interconnection Agreement with the TGSPDCL Divisional Engineer.
Turnkey Installation and MRT Meter Calibration
Supply, mechanical erection, dual chemical earthing, and protection switchgear installation. Bi-directional and generation meters submitted to TGSPDCL MRT laboratory for calibration, testing, and official sealing.
Site Inspection, Net Meter Synchronization, and Commissioning
Field inspection by TGSPDCL ADE (Operation), functional testing of anti-islanding trip relay within two seconds, physical installation of sealed meters, and issuance of Joint Commissioning Certificate.
Regulatory & Technical Guidance
Frequently asked questions for TGSPDCL
Clear answers to common questions regarding distribution transformer headroom, billing adjustment, meter testing, and safety norms.
Can I install a solar plant larger than my TGSPDCL sanctioned load?
Under TGERC regulations, rooftop solar capacity is bounded by your sanctioned contracted load. Residential consumers can install up to 100% of sanctioned load, while commercial and industrial installations are capped at 80%. If you require a higher capacity, a load enhancement application must be processed with TGSPDCL prior to or alongside the solar feasibility application.
How does TGSPDCL evaluate local transformer (DTR) feasibility?
TGSPDCL monitors cumulative solar injection on each distribution transformer. Cumulative solar capacity cannot exceed 50% of the transformer rated capacity under TSERC Regulation 6 of 2016. If the transformer is saturated, the utility issues a feasibility review detailing whether a transformer upgrade or capacity reduction is required.
Why does TGSPDCL mandate two meters for a grid-connected solar system?
TGSPDCL requires a bi-directional net meter at the consumer service point to record energy imported from and exported to the grid, plus a dedicated solar generation meter at the inverter output. The generation meter logs gross solar generation for regulatory compliance and renewable energy accounting.
How does net energy settlement reflect on TGSPDCL electricity bills?
Exported solar units are subtracted from imported grid units in each monthly billing cycle. Net positive consumption is billed at applicable retail tariff slabs. If export exceeds import, surplus credit units are banked and carried forward to subsequent billing cycles within the settlement period defined by TGERC tariff orders.
What anti-islanding safety features does TGSPDCL mandate during grid outages?
Inverters must comply with IEC 62116 / IEEE 1547 anti-islanding standards. In the event of a grid power failure, the inverter must automatically disconnect within two seconds to prevent back-feeding into de-energized distribution lines, ensuring the safety of utility maintenance staff.
Full Liaison Included
Ready to connect solar to TGSPDCL?
Leo Solar handles your roof survey, structural design, online portal registration, MRT laboratory testing, and physical bi-directional meter synchronization with Southern Power Distribution Company of Telangana Limited.
Direct consultation with our Telangana & Andhra Pradesh utility engineering team.